JP2024051462A - Light source device and projector - Google Patents

Abstract

[Problem] To provide a light source device capable of switching between a color reproducibility mode and a brightness mode. [Solution] The light source device of the present invention includes a first light source unit that emits a first light of a first wavelength band including a first polarized component and a second polarized component, a second light source unit that emits a second light of a second wavelength band, a wavelength conversion element that converts the first light into a third light of a third wavelength band, a light combining element that combines the first light, the second light, and the third light, and a filter that attenuates light of a part of the wavelength band of the third wavelength band when the third light is incident. The light combining element reflects the light of the first polarized component of the first light and transmits the light of the second polarized component, thereby emitting either the light of the first polarized component or the light of the second polarized component toward the wavelength conversion element, and transmits either the first light, the second light, or the third light and reflects the other. The filter is movable between a first position where the third light passes through the filter and a second position where the third light does not pass through the filter. [Selected figure] Figure 2

Description

The present invention relates to a light source device and a projector.

As a light source device for use in a projector, a light source device has been proposed that utilizes the fluorescence emitted from a phosphor when the phosphor is irradiated with excitation light emitted from a light-emitting element. For example, the following Patent Document 1 discloses a light source device that includes a first light source that emits blue light, a phosphor that is excited by the blue light and emits green light, a second light source that emits red light, a first dichroic mirror that transmits the blue light and reflects the green light, and a second dichroic mirror that transmits the blue light and green light and reflects the red light.

JP 2014-186115 A

In recent years, projectors are sometimes required to have a function that allows the user to select between a mode that prioritizes color reproducibility and a mode that prioritizes brightness. To realize such a projector, it is necessary to provide a light source device that can switch between a color reproducibility mode and a brightness priority mode.

When generating a specific color light, such as green light, using a phosphor as in Patent Document 1, a decrease in the purity of the green light is unavoidable compared to when a green light laser is used. As a result, color reproducibility is reduced in a projector equipped with this type of light source device. Patent Document 1 describes how red light can be effectively utilized by narrowing the band of the filter of the second dichroic mirror, but the light source device in Patent Document 1 has the problem that it cannot be switched between a color reproducibility-oriented mode and a brightness-oriented mode.

In order to solve the above problem, a light source device according to one embodiment of the present invention includes a first light source unit that emits a first light of a first wavelength band including a first polarized component and a second polarized component different from the first polarized component, a second light source unit that emits a second light of a second wavelength band different from the first wavelength band, a wavelength conversion element that converts the first light into a third light of a third wavelength band different from the first wavelength band and the second wavelength band, a light combining element that combines the first light, the second light, and the third light to emit a combined light, and a filter that receives the third light and attenuates light of a part of the wavelength band of the third wavelength band. The light combining element reflects the light of the first polarized component of the first light emitted from the first light source unit and transmits the light of the second polarized component, thereby emitting one of the light of the first polarized component and the light of the second polarized component toward the wavelength conversion element, and transmits one of the first light, the second light, and the third light, and reflects the other. The filter is movable between a first position in which the third light passes through the filter and a second position in which the third light does not pass through the filter.

A projector according to one embodiment of the present invention includes a light source device according to one embodiment of the present invention, a light modulation device that modulates the light including the composite light emitted from the light source device in accordance with image information, and a projection optical device that projects the light modulated by the light modulation device.

1 is a schematic configuration diagram of a projector according to a first embodiment. 1 is a schematic configuration diagram of a light source device according to a first embodiment. 4 is a graph showing the spectral characteristics of a first optical film of a filter. 13 is a graph showing the spectral characteristics of a second optical film of the filter. 13 is a graph showing the spectral characteristics of a third optical film of the light combining element. 13 is a graph showing the spectral characteristics of a fourth optical film of the light combining element. 13 is a graph showing the spectral characteristics of a first optical film of a filter according to a modified example. 4 is a graph showing the emission spectrum of each light source unit. 1 is a graph showing the spectrum of green light after transmission through a filter. 11 is a diagram showing the relationship between the illuminance distribution of blue light and the movement direction of a filter. FIG. 13 is a diagram showing the relationship between the illuminance distribution of green light and the movement direction of a filter. FIG. FIG. 13 is a schematic diagram illustrating the configuration of a light source device according to a second embodiment. FIG. 13 is a schematic configuration diagram of a light source device according to a third embodiment. 13 is a graph showing the spectral characteristics of a second optical film of the filter. FIG. 13 is a schematic configuration diagram of a light source device according to a fourth embodiment. 13 is a graph showing the spectral characteristics of a fifth optical film of the second light combining element. FIG. 13 is a schematic configuration diagram of a light source device according to a fifth embodiment. FIG. 2 is an enlarged view of a main part of the light source device.

[First embodiment]
A first embodiment of the present invention will be described below with reference to FIGS. 1 to 11. FIG.
The projector of this embodiment is an example of a liquid crystal projector that includes a light source device that uses a semiconductor laser and a phosphor.
In the drawings, the dimensions of the components may be shown on different scales to make them easier to see.

The projector 10 of this embodiment is a projection-type image display device that displays a color image on a screen (projection surface) SCR. The projector 10 has three light modulation devices corresponding to the colors of red light LR, green light LG, and blue light LB.

FIG. 1 is a schematic configuration diagram of a projector 10 according to the present embodiment.
As shown in FIG. 1, the projector 10 includes a light source device 100, a color separation and light-guiding optical system 200, a red light optical modulation device 400R, a green light optical modulation device 400G, a blue light optical modulation device 400B, a cross dichroic prism 500, and a projection optical device 600.

In this embodiment, the light source device 100 emits white composite light LW that includes red light LR, green light LG, and blue light LB. The specific configuration of the light source device 100 will be described later.

The color separation light guide optical system 200 includes a dichroic mirror 210, a dichroic mirror 220, a reflecting mirror 230, a reflecting mirror 240, a reflecting mirror 250, a relay lens 260, and a relay lens 270. The color separation light guide optical system 200 separates the combined light LW emitted from the light source device 100 into red light LR, green light LG, and blue light LB, and guides the red light LR to the red light optical modulation device 400R, the green light LG to the green light optical modulation device 400G, and the blue light LB to the blue light optical modulation device 400B.

A field lens 300R is disposed between the color separation light-guiding optical system 200 and the red light optical modulation device 400R. A field lens 300G is disposed between the color separation light-guiding optical system 200 and the green light optical modulation device 400G. A field lens 300B is disposed between the color separation light-guiding optical system 200 and the blue light optical modulation device 400B.

Dichroic mirror 210 transmits the red light component and reflects the green and blue light components. Dichroic mirror 220 reflects the green light component and transmits the blue light component. Reflecting mirror 230 reflects the red light component. Reflecting mirror 240 and reflecting mirror 250 each reflect the blue light component.

Each of the red light optical modulation device 400R, the green light optical modulation device 400G, and the blue light optical modulation device 400B is composed of a liquid crystal panel that forms an image by modulating the colored light incident on each optical modulation device according to image information.

Although not shown in the figure, incident side polarizing plates are arranged between the field lens 300R and the red light optical modulation device 400R, between the field lens 300G and the green light optical modulation device 400G, and between the field lens 300B and the blue light optical modulation device 400B. Also, exit side polarizing plates are arranged between the red light optical modulation device 400R and the cross dichroic prism 500, between the green light optical modulation device 400G and the cross dichroic prism 500, and between the blue light optical modulation device 400B and the cross dichroic prism 500.

The cross dichroic prism 500 combines the image light emitted from the red light optical modulation device 400R, the green light optical modulation device 400G, and the blue light optical modulation device 400B to form a color image. The cross dichroic prism 500 has a roughly square shape in a plan view formed by bonding four right-angle prisms together, and has a configuration in which a dielectric multilayer film is provided at the roughly X-shaped interface formed by bonding the right-angle prisms together.

The color image emitted from the cross dichroic prism 500 is enlarged and projected onto a projection surface such as a screen SCR by the projection optical device 600. The projection optical device 600 is composed of multiple lenses.

FIG. 2 is a schematic diagram of the light source device 100. As shown in FIG.
In the following description, an XYZ Cartesian coordinate system is used as the coordinate axes. The direction in which the composite light LW is emitted from the light source device 100 is the positive direction of the Y axis, the direction in which the blue light is emitted from the first light source unit 11 described later is the positive direction of the X axis, and the direction perpendicular to the X and Y axes, from the front to the back of the paper, is the positive direction of the Z axis.

The light source device 100 of this embodiment includes a first light source section 11, a second light source section 12, a wavelength conversion element 13, a light combining element 14, a filter 15, a parallelizing element 16, a diffusion device 17, a focusing element 18, a focusing/pickup element 19, a second retardation plate 20, an integrator optical element 21, a polarization conversion element 22, a superimposing lens 23, and a control unit 24.

The first light source unit 11 includes a first light emitting element 27, a collimator lens 28, and a first phase difference plate 29. The first light emitting element 27 is composed of a blue semiconductor laser that emits linearly polarized blue light LBs. The first light emitting element 27 emits blue light LBs of a first wavelength band in the +X direction. The first wavelength band is, for example, a blue wavelength band of 455 nm ± 10 nm. The first light emitting element 27 is mounted on a substrate 30. Although two first light emitting elements 27 are shown in FIG. 2, the number of the first light emitting elements 27 is not particularly limited. In the case of this embodiment, the blue light LBs emitted from the first light emitting element 27 is S-polarized light with respect to the light combining element 14, but may be P-polarized light LBp with respect to the light combining element 14. In the following description, the notations of S-polarized light and P-polarized light represent the polarization direction with respect to the light combining element 14 unless otherwise specified.
The blue light LBs and LBp in this embodiment correspond to the first light in the claims.

The collimator lens 28 is provided on the light emission side of the first light-emitting element 27. The collimator lens 28 is composed of one convex lens provided corresponding to one first light-emitting element 27. The collimator lens 28 collimates the blue light LBs emitted from the first light-emitting element 27.

The first phase difference plate 29 is provided on the optical path of the blue light LBs between the first light emitting element 27 and the light combining element 14. The first phase difference plate 29 imparts a phase difference to the blue light LBs. The first phase difference plate 29 is configured as a 1/2 wavelength plate for the first wavelength band of the blue light LBs. The first phase difference plate 29 is provided so as to be rotatable about an axis (axis parallel to the X-axis) perpendicular to the light incident surface 29a. Therefore, the first phase difference plate 29 is provided with a driving source such as a motor (not shown).

Since the blue light LBs emitted from the first light emitting element 27 is linearly polarized light (S-polarized component), by appropriately setting the rotation angle of the first retardation plate 29, the blue light LBs passing through the first retardation plate 29 can be converted into blue light containing S-polarized component and P-polarized component at a predetermined ratio. That is, by rotating the first retardation plate 29, the ratio of the S-polarized component and the P-polarized component can be changed. In this way, the first light source unit 11 emits blue light LBs, LBp of the first wavelength band containing S-polarized component and P-polarized component. The optical path of the principal ray of the blue light LBs, LBp emitted from the first light source unit 11 is defined as the optical axis AX1 of the first light source unit 11.
The first retardation plate 29 of this embodiment corresponds to the first retardation element in the claims. The S-polarized light component of this embodiment corresponds to the first polarized light component in the claims. The P-polarized light component of this embodiment corresponds to the second polarized light component in the claims.

The second light source unit 12 includes a second light emitting element 32 and a collimator lens 33. The second light emitting element 32 is composed of a red semiconductor laser that emits linearly polarized red light LR. The second light emitting element 32 emits red light LR of a second wavelength band in the +Y direction. The second wavelength band is, for example, a red wavelength band of 640 nm ± 10 nm. The second light emitting element 32 is mounted on a substrate 34. Although two second light emitting elements 32 are shown in FIG. 2, the number of the second light emitting elements 32 is not particularly limited. The red light LR emitted from the second light emitting element 32 may be S-polarized light or P-polarized light. The optical path of the main ray of the red light LR emitted from the second light source unit 12 is defined as the optical axis AX2 of the second light source unit 12.
The red light LR in this embodiment corresponds to the second light in the claims.

The wavelength conversion element 13 includes a green phosphor that absorbs the blue light LBp, converts it to green light LG, and emits it. That is, the wavelength conversion element 13 converts the blue light LBp emitted from the first light source unit 11 into green light LG of a third wavelength band, and emits the green light LG toward the -X direction. The third wavelength band is, for example, a green wavelength band of 470 to 650 nm. The wavelength conversion element 13 includes, as a green phosphor, a phosphor material such as, for example, Lu ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor, Y ₃ O ₄ : Eu ²⁺ phosphor, (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ phosphor, Ba ₃ Si ₆ O ₁₂ N ₂ : Eu ²⁺ phosphor, or (Si, Al) ₆ (O, N) ₈ : Eu ²⁺ phosphor. The wavelength conversion element 13 is provided on a substrate (not shown). The wavelength conversion element 13 may be provided on a rotatable substrate in an annular shape around a rotation axis. With this configuration, the temperature rise of the wavelength conversion element 13 is suppressed, the wavelength conversion efficiency is increased, and the reliability of the wavelength conversion element 13 is improved.
The green light LG in this embodiment corresponds to the third light in the claims.

The light combining element 14 is provided at a position where the optical axis AX1 of the first light source unit 11 and the optical axis AX2 of the second light source unit 12 intersect with each other. The light combining element 14 has a substrate 36, a third optical film 37 provided on one surface of the substrate 36, and a fourth optical film 38 provided on the other surface of the substrate 36. Each of the third optical film 37 and the fourth optical film 38 is composed of a dielectric multilayer film. The light combining element 14 is disposed in a direction that forms an angle of 45 degrees with each of the optical axis AX1 and the optical axis AX2.

The light combining element 14 reflects the blue light LBs of the S-polarized component and transmits the blue light LBp of the P-polarized component of the blue light LBs, LBp emitted from the first light source unit 11 by the action of the third optical film 37 and the fourth optical film 38, thereby emitting the blue light LBp of the P-polarized component toward the wavelength conversion element 13, emitting the blue light LBs of the S-polarized component toward the diffusion device 17, transmitting the blue light LBp and the red light LR, and reflecting the green light LG. As a result, the light combining element 14 combines the blue light LBp incident from the diffusion device 17 along the +Y direction, the red light LR incident from the second light source unit 12 along the +Y direction, and the green light LG incident from the wavelength conversion element 13 along the -X direction, and emits a white combined light LW toward the +Y direction. The detailed spectral characteristics of each optical film 37, 38 will be described later.
The −X direction in this embodiment corresponds to the first direction in the claims, and the +Y direction in this embodiment corresponds to the second direction in the claims.

The filter 15 is disposed on the optical axis AX2 between the light combining element 14 and the integrator optical element 21. In this embodiment, the filter 15 is disposed in a direction such that the light incident surface 15a of the filter 15 intersects at an angle of 90 degrees with the optical path of the principal ray of the combined light LW containing the green light LG. The filter 15 has a substrate 40, a first optical film 41 disposed on one surface of the substrate 40, and a second optical film 42 disposed on the other surface of the substrate 40. Each of the first optical film 41 and the second optical film 42 is composed of a dielectric multilayer film.

The filter 15 is movable in a direction (X-axis direction) perpendicular to the optical path (optical axis AX2) of the principal ray of the composite light LW. That is, the filter 15 is movable between a first position (indicated by a solid line) where the composite light LW including the green light LG passes through the filter 15, and a second position (indicated by a dashed line) where the composite light LW including the green light LG does not pass through the filter 15. The filter 15 may be configured to move automatically by a driving source such as a motor (not shown) when the user selects either the color reproducibility-oriented mode or the brightness-oriented mode, or may be configured to be moved manually by the user. When the filter 15 is located at the first position where the composite light LW including the green light LG is incident, the filter 15 attenuates the green light LG in a part of the third wavelength band (green wavelength band) by the action of the first optical film 41 and the second optical film 42. The detailed spectral characteristics of each optical film 41, 42 will be described later.

The parallelizing element 16 is provided on the optical axis AX1 between the wavelength conversion element 13 and the light combining element 14. In this embodiment, the parallelizing element 16 is composed of two convex lenses, but the number of lenses is not particularly limited. The parallelizing element 16 parallelizes the green light LG emitted from the wavelength conversion element 13, and also focuses the blue light LBp emitted from the light combining element 14 toward the wavelength conversion element 13.

The diffusion device 17 is provided on the optical axis AX2 between the light combining element 14 and the second light source unit 12. The diffusion device 17 includes a diffusion plate 44 and a motor 46 that rotates the diffusion plate 44 around a rotation axis 45. Although not shown, one surface of the diffusion plate 44 is provided with an uneven structure as a diffusion structure that diffuses the blue light LBc1 and the red light LR that are incident on the diffusion plate 44. The uneven structure may be a structure in which a plurality of concaves and convexities having irregular shapes and sizes are formed, or a structure in which a plurality of microlenses are arranged. In addition, a dichroic film that is a reflective film that reflects the blue light component and transmits the red light component is provided on the other surface of the diffusion plate 44. Note that other forms of the diffusion plate 44 may be used, such as frosted glass, a holographic diffuser, a transparent substrate that has been subjected to a blasting process, or a transparent substrate in which a scattering material is dispersed.

In this way, the light source device 100 of this embodiment includes a diffusion device 17 that diffuses the blue light LBc1 and the red light LR. With this configuration, the illuminance distribution of the blue light LBc1 and the red light LR can be made uniform, and color unevenness can be reduced. In addition, since the blue light LBc1 and the red light LR, which are coherent lights emitted from the semiconductor laser, are diffused, speckle noise of the image when applied to the projector 10 can be suppressed. Furthermore, since there is no need to separately prepare a diffusion device that diffuses the blue light LBc1 and a diffusion device that diffuses the red light LR, the number of parts of the light source device 100 can be reduced and the size can be reduced. Furthermore, since the diffusion device 17 is provided on the optical axis AX2 between the optical element 14 and the second light source unit, it is possible to suppress the light source device 100 from becoming larger in the direction intersecting the optical axis AX2 between the optical element 21 and the second light source unit 12.

The focusing element 18 is disposed on the optical axis AX2 between the second light source unit 12 and the diffusion plate 44. In this embodiment, the focusing element 18 is composed of two convex lenses, but the number of lenses is not particularly limited. The focusing element 18 focuses the red light LR emitted from the second light source unit 12 toward the diffusion plate 44.

The light collecting/pickup element 19 is provided on the optical axis AX2 between the diffuser plate 44 and the light combining element 14. In this embodiment, the light collecting/pickup element 19 is composed of two convex lenses, but the number of lenses is not particularly limited. The light collecting/pickup element 19 collects the blue light LBc1 emitted from the light combining element 14 toward the diffuser plate 44, and collimates the blue light LBc2 and red light LR diffused by the diffuser plate 44.

The second phase difference plate 20 is provided on the optical axis AX2 between the light collecting/pickup element 19 and the light combining element 14. The second phase difference plate 20 imparts a phase difference to the blue light LBs, LBc2. The second phase difference plate 20 is composed of a 1/4 wavelength plate for the first wavelength band of the blue light LBs, LBc2. As a result, the linearly polarized blue light LBs that passes through the second phase difference plate 20 is converted into circularly polarized blue light LBc1, and the circularly polarized blue light LBc2 that passes through the second phase difference plate 20 is converted into linearly polarized blue light LBp.

The integrator optical element 21 includes a first multi-lens array 48 and a second multi-lens array 49. The first multi-lens array 48 has a plurality of first lenses for splitting the combined light LW into a plurality of light beams.

The lens surface of the first multi-lens array 48, i.e., the surface of the first lens, and the image forming area of each of the light modulation devices 400R, 400G, and 400B for each color light are in a conjugate relationship with each other. Therefore, when viewed from the direction of the optical axis AX2, the shape of each of the first lenses is a rectangle that is approximately similar to the shape of the image forming area of the light modulation devices 400R, 400G, and 400B. As a result, each of the multiple light beams emitted from the first multi-lens array 48 is efficiently incident on the image forming area of each of the light modulation devices 400R, 400G, and 400B.

The second multi-lens array 49 has a plurality of second lenses corresponding to the plurality of first lenses of the first multi-lens array 48. The second multi-lens array 49, together with the superimposing lens 23, forms an image of each of the first lenses of the first multi-lens array 48 near the image forming area of each of the light modulation devices 400R, 400G, and 400B.

The combined light LW transmitted through the integrator optical element 21 is incident on the polarization conversion element 22. The polarization conversion element 22 has a configuration in which a polarization separation film, a reflective film, and a retardation plate (not shown) are arranged in an array. The polarization conversion element 22 aligns the polarization direction of the combined light LW in a predetermined direction. Specifically, the polarization conversion element 22 aligns the polarization direction of the combined light LW to the direction of the transmission axis of the incident side polarizing plate of the light modulation devices 400R, 400G, and 400B.

As a result, the polarization directions of the red light LR, green light LG, and blue light LB separated from the combined light LW transmitted through the polarization conversion element 22 coincide with the transmission axis direction of the incident-side polarizing plate of each of the light modulation devices 400R, 400G, and 400B. Therefore, the red light LR, green light LG, and blue light LB are not absorbed by the incident-side polarizing plate, and are incident on the image formation areas of the light modulation devices 400R, 400G, and 400B, respectively.

The combined light LW transmitted through the polarization conversion element 22 is incident on the superimposing lens 23. The superimposing lens 23 cooperates with the integrator optical element 21 to homogenize the illuminance distribution in the image forming areas of the light modulation devices 400R, 400G, and 400B, which are the illuminated areas.

The control unit 24 controls the current value supplied to each of the first light-emitting element 27 of the first light source unit 11 and the second light-emitting element 32 of the second light source unit 12. Specifically, the control unit 24 individually controls the current value supplied to each of the first light source unit 11 and the second light source unit 12 when the filter 15 is placed in the first position, and the current value supplied to each of the first light source unit 11 and the second light source unit 12 when the filter 15 is placed in the second position. Specific examples of control will be described later. Furthermore, the control unit 24 may control items such as the movement of the filter 15, the rotation angle of the first retardation plate 29, and the rotation speed of the diffusion plate 44 when either the color reproducibility mode or the brightness mode is selected.

The behavior of the light emitted from each of the first light source unit 11 and the second light source unit 12 will be described below.
As described above, in the first light source unit 11, the blue light LBs of the S-polarized component emitted from the first light-emitting element 27 is converted into blue light LBs, LBp in which the S-polarized component and the P-polarized component are mixed at a predetermined ratio by transmitting through the first phase difference plate 29. Of these, the blue light LBp of the P-polarized component transmits through the light combining element 14 and enters the wavelength conversion element 13 in a state where it is collected by the parallelizing element 16. In the wavelength conversion element 13, the green phosphor is excited by the blue light LBp, and green light LG is emitted. The green light LG emitted from the wavelength conversion element 13 is parallelized by the parallelizing element 16, reflected by the light combining element 14, and proceeds toward the filter 15.

On the other hand, the S-polarized blue light LBs is reflected by the light combining element 14 and converted into a predetermined circularly polarized light, for example, right-handed circularly polarized blue light LBc1, by passing through the second phase difference plate 20. The right-handed circularly polarized blue light LBc1 is collected by the light collecting/pickup element 19 and enters the diffusion plate 44. The right-handed circularly polarized blue light LBc1 that enters the diffusion plate 44 is diffused by the diffusion plate 44 and converted into left-handed circularly polarized blue light LBc2. The left-handed circularly polarized blue light LBc2 is collimated by the light collecting/pickup element 19 and then converted into P-polarized blue light LBp by passing through the second phase difference plate 20. The P-polarized blue light LBp passes through the light combining element 14 and proceeds toward the filter 15.

In the second light source unit 12, the red light LR emitted from the second light emitting element 32 is focused by the focusing element 18 and enters the diffusion plate 44, where it is diffused. The diffused red light LR is collimated by the focusing/pickup element 19, then passes through the second phase difference plate 20, passes through the light combining element 14, and proceeds toward the filter 15. Note that since the second phase difference plate 20 is optimized for the blue wavelength band, the polarization state does not change significantly even when the red light LR passes through the second phase difference plate 20. Furthermore, the light combining element 14 transmits the red light LR regardless of the polarization state of the red light LR.

As described above, the blue light LBp, the green light LG, and the red light LR are combined by the light combining element 14. The light combining element 14 emits white combined light LW.

The spectral characteristics of the filter 15 and the optical films of the light combining element 14 will be described below.
Fig. 3 is a graph showing the spectral characteristics of the first optical film 41 of the filter 15. Fig. 4 is a graph showing the spectral characteristics of the second optical film 42 of the filter 15. Fig. 5 is a graph showing the spectral characteristics of the third optical film 37 of the light combining element 14. Fig. 6 is a graph showing the spectral characteristics of the fourth optical film 38 of the light combining element 14. In Figs. 3 to 6, the horizontal axis is wavelength (nm) and the vertical axis is transmittance (%).
Fig. 8 is a graph showing the emission spectra of the light source units 11 and 12. Fig. 9 is a graph showing the spectrum of the green light LG after passing through the filter 15. In Figs. 8 and 9, the horizontal axis is wavelength (nm) and the vertical axis is relative luminance (-).

As shown in FIG. 8, the first light-emitting element 27 of the first light source unit 11 emits blue light LBs in the blue wavelength band of 455 nm±10 nm. The second light-emitting element 32 of the second light source unit 12 emits red light LR in the red wavelength band of 640 nm±10 nm. The wavelength conversion element 13 emits green light LG in the green wavelength band of 470 to 650 nm.

As shown in FIG. 3, for the above emission spectrum, the first optical film 41 of the filter 15 cuts out the short-wavelength components of the green light LG emitted from the wavelength conversion element 13, that is, components on the short wavelength side of about 470 to 520 nm, and transmits the components in the remaining wavelength band. Furthermore, the first optical film 41 transmits blue light LBp with a central wavelength of 455 nm and red light LR with a central wavelength of 640 nm. In this way, the first optical film 41 contributes to cutting out the short-wavelength components of the green light LG.

As shown in FIG. 4, the second optical film 42 of the filter 15 cuts out the long wavelength components of about 540 to 620 nm of the green light LG emitted from the wavelength conversion element 13, and transmits the remaining wavelength band components. Furthermore, the second optical film 42 transmits blue light LBp with a central wavelength of 455 nm and red light LR with a central wavelength of 640 nm. In this way, the second optical film 42 contributes to cutting out the long wavelength components of the green light LG.

By the action of the two optical films 41, 42, the filter 15 cuts out the short wavelength component of 470 to 520 nm and the long wavelength component of 540 to 620 nm of the green light LG in the third wavelength band of 470 to 650 nm emitted from the wavelength conversion element 13. As a result, as shown in FIG. 9, the filter 15 can narrow the wavelength band of the green light LG to about 530 nm ± 20 nm.

As shown in FIG. 5, the third optical film 37 of the light combining element 14 transmits the P-polarized component of the blue light LBs, LBp in the first wavelength band and reflects the S-polarized component of the light. The third optical film 37 also transmits the red light LR in the second wavelength band and the green light LG in the third wavelength band. In this way, the third optical film 37 functions as a polarization separation film for the blue light LBs, LBp.

As shown in FIG. 6, the fourth optical film 38 of the light combining element 14 transmits blue light LBp in the first wavelength band, reflects green light LG in the third wavelength band, and transmits red light LR in the second wavelength band. Furthermore, the fourth optical film 38 transmits the longer wavelength component of the green light LG in the third wavelength band. In this way, the fourth optical film 38 functions as a wavelength selection film.

By the action of the two optical films 37, 38, the light combining element 14 can realize the function of transmitting the P-polarized component of the blue light LBp and reflecting the S-polarized component of the blue light LBs and LBp emitted from the first light source unit 11, as well as transmitting the red light LR and reflecting the green light LG.

Instead of the above configuration, the filter 15 may have the following configuration.
FIG. 7 is a graph showing the spectral characteristics of the first optical film of the filter of the modified example.
Although not shown in the drawings, the filter of the modified example has a substrate, a first optical film provided on one surface of the substrate, and an anti-reflection film provided on the other surface of the substrate.

As shown in FIG. 7, the first optical film of the modified filter transmits only the 520-550 nm component of the green light LG in the wavelength band of 470-650 nm emitted from the wavelength conversion element 13. The first optical film also transmits blue light LBp with a central wavelength of 455 nm and red light LR with a central wavelength of 640 nm.

As described above, the green light LG contained in the combined light LW emitted from the light combining element 14 is narrowed in band and its color purity is improved by passing through the filter 15. On the other hand, the blue light LBp and the red light LR are originally narrow band lights derived from semiconductor lasers, and their color purity remains high even after passing through the filter 15. Therefore, if the filter 15 is placed in the optical path of the combined light LW, the color gamut of the combined light LW is expanded, and color reproducibility can be improved. On the other hand, if the filter 15 is placed outside the optical path of the combined light LW, some components of the green light LG are not cut by the filter 15, and the brightness of the combined light LW can be increased.

The light source device 100 of this embodiment is provided with a collimating element 16 that is provided on the light incident side of the filter 15 and that approximately collimates the green light LG emitted from the wavelength conversion element 13. Furthermore, the light source device 100 is provided with a light collecting/pickup element 19 that is provided on the light incident side of the filter 15 and that approximately collimates the blue light LBc2 and the red light LR emitted from the diffusion plate 44. The filter 15 is also arranged in such a direction that the light incident surface 15a intersects with the optical path of the principal ray of the combined light LW containing the green light LG at an angle of 90 degrees. With this configuration, the combined light LW is perpendicularly incident on the light incident surface 15a of the filter 15. As a result, it is not necessary to consider the incidence angle dependency of light when designing each optical film 41, 42 of the filter 15, so that it is easy to improve the characteristics of the filter 15 and to manufacture the filter 15.

A specific example of the control of the current values to the light sources 11 and 12 by the control unit 24 will be described below.
In the inventor's study, the color temperature of a projector using a specific optical system is set to 6500 K, and the deviation is set to 0.003. If the color gamut satisfies the DCI-P3 standard when the filter 15 is not inserted in the optical path, the balance of the light amounts of the respective color lights to ensure a predetermined white balance is red light: green light: blue light = 160%: 100%: 58%.

Next, suppose that filter 15 is placed in the light path to improve color reproducibility. At this time, part of the green light LG is cut by filter 15, so the amount of green light LG decreases. In this case, to ensure the same white balance as when filter 15 is not placed in the light path, it is necessary to reduce the amount of red light LR and blue light LBp in accordance with the decrease in the amount of green light LG. Therefore, the balance of light amounts when filter 15 is placed in the light path is red light: green light: blue light = 75%: 100%: 15.9%.

In this way, when the filter 15 is inserted in the optical path, the balance between the amount of green light LG and the amount of blue light LBp changes from the state when the filter 15 is not inserted in the optical path. Therefore, the balance between the amount of green light LG and the amount of blue light LBp is adjusted by rotating the first retardation plate 29 to change the light ratio between the P-polarized component and the S-polarized component. Furthermore, when the filter 15 is inserted in the optical path, the balance between the amount of green light LG and the amount of red light LR also changes from the state when the filter 15 is not inserted in the optical path. Therefore, the control unit 24 controls the current value supplied to the second light-emitting element 32 when the filter 15 is inserted in the optical path to be smaller than the current value supplied to the second light-emitting element 32 when the filter 15 is not inserted in the optical path.

Here, when the light source device 100 has a configuration in which current is distributed from one power source to the first light-emitting element 27 and the second light-emitting element 32, reducing the current value supplied to the second light-emitting element 32 increases the margin of the power capacity of the power source, making it possible to distribute a larger current to the first light-emitting element 27. At this time, the control unit 24 performs control so that the current value supplied to the first light-emitting element 27 when the filter 15 is placed in the optical path is greater than the current value supplied to the first light-emitting element 27 when the filter 15 is not placed in the optical path.

In the light source device 100 of this embodiment, the control unit 24 performs the above control, thereby adjusting the white balance of the composite light LW emitted from the light source device 100 while minimizing the decrease in brightness when the filter 15 is placed in the light path.

A preferred moving direction of the filter 15 will now be described with reference to FIGS.
Fig. 10 is a diagram showing the relationship between the illuminance distribution of blue light LBp on filter 15 and the movement direction of filter 15. Fig. 11 is a diagram showing the relationship between the illuminance distribution of green light LG on filter 15 and the movement direction of filter 15.

Generally, the cross-sectional shape of light emitted from a semiconductor laser is an ellipse having a major axis and a minor axis. In this specification, the cross-sectional shape of light is defined as the cross-sectional shape in a direction perpendicular to the principal ray of the light. Therefore, in this embodiment, the cross-sectional shape of the blue light LBp at the time of entering the filter 15 varies slightly depending on the number and arrangement of the first light-emitting elements 27, but even if diffused by the diffuser plate 44, it does not become circular, and in most cases maintains an elliptical shape as shown in FIG. 10.

On the other hand, since the green light LG is isotropically emitted from the wavelength conversion element 13 as Lambertian light, the cross-sectional shape of the green light LG at the time of entering the filter 15 often maintains a circular shape as shown in FIG. 11. In addition, in order to suppress color unevenness in the optical system subsequent to the filter 15, the diameter D1 of the cross-sectional shape of the green light LG is made to approximately match either the diameter D2 in the direction along the major axis of the cross-sectional shape of the blue light LBp or the diameter D3 in the direction along the minor axis of the cross-sectional shape of the blue light LBp. In the examples of FIG. 10 and FIG. 11, the diameter D1 of the cross-sectional shape of the green light LG is made to approximately match the diameter D2 in the direction along the major axis of the cross-sectional shape of the blue light LBp. Conversely, the diameter D1 of the cross-sectional shape of the green light LG may be made to approximately match the diameter D3 in the direction along the minor axis of the cross-sectional shape of the blue light LBp.

As shown in Figures 10 and 11, suppose that the filter 15 is moved in a direction along the short axis of the cross-sectional shape of the blue light LBp (horizontal direction in the figure). In this case, as shown on the right side of the figure, during the movement of the filter 15, there is a time when the blue light LBp passes through the filter 15 in all areas, while the green light LG does not pass through the filter 15 in some areas. This may cause color unevenness during the movement of the filter 15 when switching modes. Therefore, if the filter 15 is moved in a direction along the long axis of the cross-sectional shape of the blue light LBp (vertical direction in the figure), a situation will not occur in which one light passes through the filter 15 in all areas and the other light does not pass through the filter 15 in some areas. This makes it possible to suppress the occurrence of color unevenness during the movement of the filter 15. That is, when the diameter D1 of the cross-sectional shape of the green light LG is approximately equal to either the diameter D2 along the major axis of the cross-sectional shape of the blue light LBp or the diameter D3 along the minor axis, it is desirable to move the filter 15 in the direction along the axis that is approximately equal to either the direction along the major axis or the direction along the minor axis.

[Effects of the First Embodiment]
The light source device 100 of this embodiment includes a first light source unit 11 that emits blue light LBs, LBp in a first wavelength band including an S-polarized component and a P-polarized component, a second light source unit 12 that emits red light LR in a second wavelength band, a wavelength conversion element 13 that converts the blue light LBp into green light LG in a third wavelength band, a light combining element 14 that combines the blue light LBp, red light LR, and green light LG to emit combined light LW, and a filter 15 that attenuates light in a portion of the third wavelength band when green light LG is incident. The light combining element 14 reflects the S-polarized blue light LBs and transmits the P-polarized blue light LBp out of the blue light LBs, LBp emitted from the first light source unit 11, thereby emitting the P-polarized blue light LBp toward the wavelength conversion element 13 and emitting the S-polarized blue light LBs toward the diffusion device 17, transmitting the blue light LBp and the red light LR, and reflecting the green light LG. The filter 15 is movable between a first position where the green light LG transmits through the filter 15 and a second position where the green light LG does not transmit through the filter 15.

According to this configuration, as described above, at the first position where the green light LG passes through the filter 15, the light of a part of the wavelength band of the green light LG is attenuated, narrowing the band of the green light LG and improving the color purity. This widens the color gamut of the composite light LW, and improves color reproducibility. On the other hand, at the second position where the green light LG does not pass through the filter 15, the light of a part of the wavelength band of the green light LG is not attenuated by the filter 15, so that the brightness of the composite light LW can be increased. In this way, by moving the filter 15 between the first position and the second position, the characteristics of the composite light LW emitted from the light source device 100 can be changed. As a result, when the light source device 100 is applied to the projector 10, the movement of the filter 15 can switch between a color reproducibility-oriented mode and a brightness-oriented mode.

The projector 10 of this embodiment includes the light source device 100 of this embodiment, light modulation devices 400R, 400G, and 400B that modulate the light including the composite light LW emitted from the light source device 100 in accordance with image information, and a projection optical device 600 that projects the light modulated by the light modulation devices 400R, 400G, and 400B.

With this configuration, the light source device 100 can switch between a color reproducibility-oriented mode and a brightness-oriented mode, realizing a projector 10 that can be used by the user for different purposes, for example, to enhance the expressiveness of images when watching movies, etc., and to display documents, etc., in a bright room.

[Second embodiment]
A second embodiment of the present invention will be described below with reference to FIG.
The basic configuration of the projector of the second embodiment is similar to that of the first embodiment, but the configuration of the light source device is different from that of the first embodiment, so a description of the basic configuration of the projector will be omitted.

FIG. 12 is a schematic diagram of a light source device 120 according to the second embodiment.
In FIG. 12, the same components as those in FIG. 2 used in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 12, the light source device 120 of this embodiment includes a first light source unit 11, a second light source unit 12, a wavelength conversion element 13, a light combining element 14, a filter 15, a parallelizing element 16, a diffusion device 17, a focusing element 18, a focusing/pickup element 19, a second retardation plate 20, an integrator optical element 21, a polarization conversion element 22, a superimposing lens 23, and a control unit 24.

In the first embodiment, the filter 15 is arranged so that the light incident surface 15a intersects the optical path of the chief ray of the composite light LW containing the green light LG at an angle of 90 degrees. In contrast, in the present embodiment, the filter 15 is arranged so that the light incident surface 15a is tilted so that it intersects the optical path (optical axis AX2) of the chief ray of the composite light LW containing the green light LG at an angle other than 90 degrees. The other configurations of the light source device 120 are the same as those of the first embodiment.

[Effects of the second embodiment]
In the light source device 120 of this embodiment, the characteristics of the synthetic light LW emitted from the light source device 120 can be changed by moving the filter 15 between the first position and the second position, and when applied to the projector 10, the same effect as in the first embodiment can be obtained, that is, the color reproducibility-oriented mode and the brightness-oriented mode can be switched between.

Furthermore, in this embodiment, the light incidence surface 15a of the filter 15 is inclined in a direction intersecting the optical path of the principal ray of the composite light LW containing the green light LG at an angle other than 90 degrees. With this configuration, a part of the composite light LW reflected by the filter 15 travels a different path from the composite light LW incident on the filter 15, so that the light that returns to the wavelength conversion element 13 and each of the light emitting elements 27, 32 after being reflected by the filter 15 can be reduced. This can improve the reliability of the wavelength conversion element 13 and each of the light emitting elements 27, 32. For example, the light traveling toward the wavelength conversion element 13 may be configured to be incident on the support substrate of the wavelength conversion element 13. With this configuration, heat generated by the reflected light can be released from the support substrate, and the reliability of the wavelength conversion element 13 can be improved.

[Third embodiment]
A third embodiment of the present invention will be described below with reference to FIGS.
The basic configuration of the projector of the third embodiment is similar to that of the first embodiment, but the configuration of the light source device is different from that of the first embodiment, so a description of the basic configuration of the projector will be omitted.

FIG. 13 is a schematic diagram of a light source device 130 according to the third embodiment.
In FIG. 13, the same components as those in FIG. 2 used in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 13, the light source device 130 of this embodiment includes a first light source unit 11, a second light source unit 12, a wavelength conversion element 13, a light combining element 14, a filter 55, a parallelizing element 16, a diffusing device 17, a focusing element 18, a focusing/pickup element 19, a second retardation plate 20, an integrator optical element 21, a polarization conversion element 22, a superimposing lens 23, and a control unit 24.

The light source device 130 of this embodiment differs from the light source device 100 of the first embodiment in the position of the filter 55. Specifically, in this embodiment, the filter 55 is provided on the optical axis AX1 between the light combining element 14 and the wavelength conversion element 13. In the first embodiment, the combined light LW combined by the light combining element 14, i.e., all colored light, enters the filter 55. In contrast, in this embodiment, the green light LG before being combined by the light combining element 14 and the blue light LBp emitted from the light combining element 14 enter the filter 55, and the red light LR does not enter the filter 55. The other configurations of the light source device 130 are the same as those of the first embodiment.

Figure 14 is a graph showing the spectral characteristics of the second optical film 56 of the filter 55 of this embodiment. In Figure 14, the horizontal axis is wavelength (nm) and the vertical axis is transmittance (%).

As shown in FIG. 14, the second optical film 56 of the filter 55 cuts out the long-wavelength component of 550 nm or more of the green light LG emitted from the wavelength conversion element 13. The first optical film 41 is the same as the first optical film 41 of the first embodiment (see FIG. 3). Due to the action of the two optical films 56, 41, the filter 55 cuts out the short-wavelength component of 470 to 520 nm and the long-wavelength component of 550 nm or more of the green light in the third wavelength band of 470 to 650 nm emitted from the wavelength conversion element 13. This allows the filter 55 to narrow the band of the green light LG.

[Effects of the third embodiment]
In the light source device 130 of this embodiment, the characteristics of the synthetic light LW emitted from the light source device 130 can be changed by moving the filter 55 between the first position and the second position, and when applied to the projector 10, the same effect as in the first embodiment can be obtained, that is, the color reproducibility-oriented mode and the brightness-oriented mode can be switched between.

In the present embodiment, the second optical film 42 of the first embodiment can be used as the second optical film of the filter 55, but it is preferable to use the second optical film 56 having the spectral characteristics shown in FIG. 14 described above. According to this configuration, the second optical film 56 does not need to transmit the red light LR while cutting the long wavelength components of the green light LG, so the specifications of the second optical film 56 are simpler than the specifications of the second optical film 42 of the first embodiment shown in FIG. 4. This makes it possible to reduce the manufacturing cost of the filter 55 and to easily achieve the desired spectral characteristics.

[Fourth embodiment]
A fourth embodiment of the present invention will be described below with reference to FIGS.
The basic configuration of the projector of the fourth embodiment is similar to that of the first embodiment, but the configuration of the light source device is different from that of the first embodiment, so a description of the basic configuration of the projector will be omitted.

FIG. 15 is a schematic diagram of a light source device 140 according to the fourth embodiment.
In FIG. 15, the same components as those in FIG. 2 used in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 15, the light source device 140 of this embodiment includes a first light source unit 11, a second light source unit 12, a wavelength conversion element 13, a light combining element 64, a filter 15, a parallelizing element 16, a diffusion device 65, a focusing element 18, a focusing/pickup element 19, a second retardation plate 20, an integrator optical element 21, a polarization conversion element 22, a superimposing lens 23, and a control unit 24. In the light source device 140 of this embodiment, the configuration of the light combining element 64, the position of the second light source unit 12, and the configuration of the diffusion device 65 are all different from those of the light source device 100 of the first embodiment.

In this embodiment, the light combining element 64 is composed of a first light combining element 67 and a second light combining element 68. The configuration and optical characteristics of the first light combining element 67 are the same as those of the light combining element 14 in the first embodiment. In addition, the positional relationship of the first light source unit 11, the wavelength conversion element 13, and the diffusion device 65 with respect to the first light combining element 67 is also the same as in the first embodiment.

The axis along the principal ray of the light emitted from the diffuser plate 70 is defined as the optical axis AX3. The optical axis AX3 coincides with the optical axes of the integrator optical element 21, the polarization conversion element 22, the superposition lens 23, etc. In the first embodiment, the optical axis AX1 of the first light source unit 11 and the optical axis AX2 of the second light source unit 12 are perpendicular to each other. In contrast, in this embodiment, the optical axis AX1 of the first light source unit 11 and the optical axis AX2 of the second light source unit 12 are arranged parallel to the X-axis and are parallel to each other, and are perpendicular to the optical axis AX3 that is parallel to the Y-axis.

The second light combining element 68 is provided on the optical axis AX3 between the first light combining element 67 and the filter 15. The second light combining element 68 is provided at a position where the optical axis AX2 and the optical axis AX3 of the second light source unit 12 intersect with each other. The second light combining element 68 has a substrate 72, a fifth optical film 73 provided on one surface of the substrate 72, and an anti-reflection film 74 provided on the other surface of the substrate 72. The fifth optical film 73 is composed of a dielectric multilayer film. The second light combining element 68 is arranged such that the plate surface of the substrate 72 forms an angle of 45 degrees with respect to each of the optical axis AX2 and the optical axis AX3. A red light diffusion plate 76 for diffusing the red light LR is provided on the optical axis AX2 between the second light source unit 12 and the second light combining element 68.

Fig. 16 is a graph showing the spectral characteristics of the fifth optical film 73 of the second light combining element 68. In Fig. 16, the horizontal axis represents wavelength (nm) and the vertical axis represents transmittance (%).
As shown in FIG. 16, the second light combining element 68 reflects the S-polarized red light LRs, transmits the P-polarized red light LRp, and transmits the blue light LBp and green light LG due to the action of the fifth optical film 73.

The diffuser 44 of the first embodiment functions as a reflective diffuser for the blue light LBc1 and as a transmissive diffuser for the red light LR, so a dichroic film that reflects the blue light LBc1 and transmits the red light LR was required. In contrast, the diffuser 70 of the present embodiment only needs to function as a reflective diffuser for both the blue light LBc1 and the red light LRc1, so the above-mentioned dichroic film is not required, and a reflective film (not shown) is provided instead of the above-mentioned dichroic film.

The behavior of each color of light will be described below.
The behavior of the blue light LBs emitted from the first light source unit 11 and the green light LG emitted from the wavelength conversion element 13 is similar to that of the light source device 100 of the first embodiment, and therefore a description thereof will be omitted.

In the second light source unit 12, the red light LRs of the S-polarized component emitted from the second light-emitting element 32 is diffused by the red light diffuser 76, reflected by the second light combiner 68, and transmitted through the first light combiner 67. The red light LRs of the S-polarized component emitted from the first light combiner 67 is converted into a predetermined circularly polarized light, for example, right-handed circularly polarized red light LRc1, by transmitting through the second phase difference plate 20, similar to the blue light LBs of the S-polarized component emitted from the first light source unit 11. In the case of this embodiment, the second phase difference plate 20 imparts a phase difference to both the blue light LBs and the red light LRs. The right-handed circularly polarized red light LRc1 is incident on the diffuser 70 in a state where it is collected by the light collection/pickup element 19. The right-handed circularly polarized red light LRc1 is diffused by the diffuser 70 and converted into left-handed circularly polarized red light LRc2. The left-handed circularly polarized red light LRc2 is collimated by the light collection/pickup element 19, and then passes through the second retardation plate 20, where it is converted into P-polarized red light LRp. The P-polarized red light LRp passes through the first light combining element 67, passes through the second light combining element 68, and travels toward the filter 15.

As described above, the blue light LBp, the green light LG, and the red light LRp are combined by the light combining element 64, which is composed of the first light combining element 67 and the second light combining element 68. White combined light LW is emitted from the light combining element 64. The function of the filter 15 is the same as in the first embodiment.

[Effects of the Fourth Embodiment]
In the light source device 140 of this embodiment, the characteristics of the synthetic light LW emitted from the light source device 140 can be changed by moving the filter 15 between the first position and the second position, and when applied to the projector 10, the same effect as in the first embodiment can be obtained, that is, the color reproducibility-oriented mode and the brightness-oriented mode can be switched between.

In this embodiment, the filter 15 is provided on the optical axis AX3 between the second light combining element 68 and the integrator optical element 21, but instead, it may be provided on the optical axis AX3 between the first light combining element 67 and the second light combining element 68.

[Fifth embodiment]
A fifth embodiment of the present invention will be described below with reference to FIGS.
The basic configuration of the projector of the fifth embodiment is similar to that of the first embodiment, but the configuration of the light source device is different from that of the first embodiment, so a description of the basic configuration of the projector will be omitted.

FIG. 17 is a schematic diagram of a light source device 150 according to the fifth embodiment.
In FIG. 17, the same components as those in FIG. 2 used in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 17, the light source device 150 of this embodiment includes a first light source unit 11, a second light source unit 12, a wavelength conversion element 13, a light combining element 14, a filter 85, a parallelizing element 16, a diffusing device 17, a focusing element 18, a focusing/pickup element 19, a second retardation plate 20, an integrator optical element 21, a polarization conversion element 22, a superimposing lens 23, and a control unit 24.

The light source device 150 of this embodiment differs from the light source device 100 of the first embodiment in the position and configuration of the filter 85. Specifically, in this embodiment, the filter 85 is provided on the optical axis AX2 between the integrator optical element 21 and the polarization conversion element 22. In other words, the integrator optical element 21 is provided on the light incident side of the filter 85. The polarization conversion element 22 is provided on the light exit side of the filter 85. In addition, it is desirable to place the filter 85 in a position close to the polarization conversion element 22.
The integrator optical element 21 of this embodiment corresponds to a first optical element in the claims, and the polarization conversion element 22 of this embodiment corresponds to a second optical element in the claims.

Figure 18 is an enlarged view showing the filter 85 and the vicinity of the polarization conversion element 22. In Figure 18, the filter 85 when placed in the first position is shown by a solid line, and the filter 85 when placed in the second position is shown by a dashed line. In order to make the drawing easier to see, the positions of the filter 85 placed in the first position and the filter 85 placed in the second position are shown shifted in the light traveling direction.

As described in the first embodiment, the first multi-lens array 48 of the integrator optical element 21 splits the combined light LW emitted from the light combining element 14 into multiple light beams, and causes the multiple light beams to enter the second multi-lens array 49. Therefore, as shown in FIG. 18, the multiple light beams constituting the combined light LW are emitted from the second multi-lens array 49. Here, any two adjacent light beams among the multiple light beams are referred to as the first light beam L1 and the second light beam L2.

On the other hand, the polarization conversion element 22 has a configuration in which a plurality of polarization separation films 87 and a plurality of reflective films 88 are alternately arranged, and each of the plurality of light beams must be incident on each of the plurality of polarization separation films 87. Therefore, the polarization conversion element 22 has a plurality of light entrance areas corresponding to the plurality of polarization separation films 87. In the polarization conversion element 22 shown in FIG. 18, the light entrance area where the first light beam L1 is incident is the first light entrance area 22A, and the light entrance area where the second light beam L2 is incident is the second light entrance area 22B.

The filter 85 has a substrate 90, a first optical film 91 provided on one surface of the substrate 90, and a second optical film 92 provided on the other surface of the substrate 90. Each of the first optical film 91 and the second optical film 92 is composed of a dielectric multilayer film. In the first to fourth embodiments, each of the first optical film and the second optical film is provided on the entire surface of the substrate, whereas in this embodiment, each of the first optical film 91 and the second optical film 92 is divided and provided so as to correspond to each of the multiple light incidence areas of the polarization conversion element 22. Therefore, in the following description, one area of the filter 85 where the divided first optical film 91 and second optical film 92 are provided is referred to as a filter section. The filter section into which the first light beam L1 is incident is referred to as the first filter section 85A, and the filter section into which the second light beam L2 is incident is referred to as the second filter section 85B. The spectral characteristics of the first optical film 91 and the second optical film 92 are the same as the spectral characteristics of the first optical film 41 and the second optical film 42 in the first embodiment.

In this embodiment, as shown by the solid line in FIG. 18, in the first position of the filter 85, the first filter section 85A is disposed in a position facing the first light entrance area 22A of the polarization conversion element 22, and the second filter section 85B is disposed in a position facing the second light entrance area 22B of the polarization conversion element 22. At this time, the composite light LW including the green light LG passes through the filter 85. Also, as shown by the dashed line in FIG. 18, in the second position of the filter 85, the first filter section 85A is disposed in a position facing the area between the first light entrance area 22A and the second light entrance area 22B of the polarization conversion element 22. At this time, the composite light LW including the green light LG does not pass through the filter 85, but passes through the substrate 90 between the two adjacent filter sections.

[Effects of the Fifth Embodiment]
In the light source device 150 of this embodiment, the characteristics of the synthetic light LW emitted from the light source device 150 can be changed by moving the filter 85 between the first position and the second position, and when applied to the projector 10, the same effect as in the first embodiment can be obtained, that is, the color reproducibility-oriented mode and the brightness-oriented mode can be switched between.

In the light source device 150 of this embodiment, when the filter 85 is moved between the first position and the second position, there is no need to move the entire filter 85 to the outside of the area through which multiple light beams pass, but it is sufficient to move it by the width of one light entrance area of the polarization conversion element 22. In this way, in the case of this embodiment, the movement distance of the filter 85 can be made smaller than in the light source devices of the first to fourth embodiments, so the light source device 150 can be made more compact.

The technical scope of the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the spirit of the present invention. In addition, one aspect of the present invention can be a configuration that appropriately combines the characteristic parts of each of the above-mentioned embodiments.

For example, the light combining element of the first embodiment has the property of transmitting blue light and red light and reflecting green light, but it may have the opposite property of reflecting blue light and red light and transmitting green light. The light source device is provided with a diffusion device that diffuses both blue light and red light, but instead of this configuration, it may be provided with a diffusion device that diffuses blue light and a diffusion device that diffuses red light separately. The first light source unit does not necessarily have to include a first retardation plate, and for example, a first light emitting element that emits a P-polarized component of blue light and a first light emitting element that emits an S-polarized component of blue light may be mixed in the first light source unit.

The specific description of the shape, number, arrangement, material, etc. of each component of the light source device and the projector is not limited to the above embodiment and can be modified as appropriate. In addition, the above embodiment shows an example in which the light source device according to the present invention is mounted on a projector using a liquid crystal panel, but this is not limited to this. The light source device according to the present invention may be applied to a projector that uses a digital micromirror device as a light modulation device. In addition, the projector does not need to have multiple light modulation devices, and may be a single-panel projector that has only one light modulation device.

In the above embodiment, an example was shown in which the light source device of the present invention was applied to a projector, but this is not limited to this. The light source device of the present invention can also be applied to lighting fixtures, automobile headlights, etc.

[Summary of the Disclosure]
The following is a summary of this disclosure.

(Appendix 1)
a first light source unit that emits a first light of a first wavelength band including a first polarized component and a second polarized component different from the first polarized component;
a second light source unit that emits a second light of a second wavelength band different from the first wavelength band;
a wavelength conversion element that converts the first light into a third light of a third wavelength band different from the first wavelength band and the second wavelength band;
a light combining element that combines the first light, the second light, and the third light and emits a combined light;
a filter into which the third light is incident and which attenuates light of a part of the third wavelength band;
Equipped with
The light combining element is
The first light emitted from the first light source unit is reflected by the first polarization component, and the second polarization component is transmitted, thereby emitting one of the first polarization component and the second polarization component toward the wavelength conversion element;
transmits one of the first light, the second light, and the third light, and reflects the other,
The filter comprises:
A light source device that is movable between a first position where the third light passes through the filter and a second position where the third light does not pass through the filter.

According to the configuration of Appendix 1, the characteristics of the composite light emitted from the light source device can be changed by moving the filter between the first position and the second position.

(Appendix 2)
2. The light source device of claim 1, further comprising a diffusion device that diffuses the first light and the second light.

According to the configuration of Supplementary Note 2, the illuminance distribution of the first light and the second light can be made uniform, and color unevenness can be reduced. Furthermore, when each light source unit has a laser light source, speckle noise in an image can be suppressed when the light source device is applied to a projector. Furthermore, since there is no need to separately prepare a diffusion device for diffusing the first light and a diffusion device for diffusing the second light, the number of parts in the light source device can be reduced and the size can be reduced.

(Appendix 3)
the diffusion device is disposed between the light combining element and the second light source unit,
The light source device described in Appendix 2, wherein the diffusion device has a diffusion structure that diffuses the first light and the second light on a surface on which the first light reflected by the light combining element is incident, and has a reflective film on a surface opposite the light incident surface that reflects the first light and transmits the second light.

According to the configuration of Supplementary Note 3, even if a diffusion device is provided, it is possible to prevent the light source device from becoming large in size in the direction intersecting the optical axis between the light combining element and the second light source unit.

(Appendix 4)
4. The light source device according to claim 1, further comprising a collimating element provided on a light incident side of the filter to substantially collimate the third light.

The configuration of Appendix 4 makes it easier to improve the characteristics of the filter because it is not necessary to take into account the incidence angle dependency of light when designing the filter.

(Appendix 5)
5. The light source device according to claim 1, wherein a light incident surface of the filter intersects with a chief ray of the third light at an angle other than 90 degrees.

The configuration of Appendix 4 makes it possible to reduce the amount of light that returns to the wavelength conversion element and each light source unit after being reflected by the filter. This makes it possible to improve the reliability of the wavelength conversion element and each light source unit.

(Appendix 6)
The first light source unit is
A first light emitting element that emits the first light;
a first phase difference element provided between the first light emitting element and the light combining element and configured to impart a phase difference to the first light;
Equipped with
the first light emitted from the light combining element is incident on the wavelength conversion element,
6. The light source device according to claim 1, wherein the first phase difference element is rotatable about an axis that intersects with a light incident surface of the first phase difference element.

According to the configuration of Appendix 6, the ratio between the first polarized component and the second polarized component can be changed by rotating the first phase difference element, and the proportion of the first light incident on the wavelength conversion element can be changed.

(Appendix 7)
The light source device according to any one of Supplementary Note 1 to Supplementary Note 6, further comprising a control unit that individually controls a current value supplied to the first light source unit when the filter is located at the first position and a current value supplied to the first light source unit when the filter is located at the second position so that they are different from each other.

According to the configuration of Appendix 7, the control unit can individually control the current value supplied to the first light source unit depending on whether the filter is in the first position or the second position.

(Appendix 8)
the first light is blue light;
the second light is red light;
the third light is green light;
The light source device described in Appendix 7, wherein the control unit controls the current value supplied to the first light source unit when the filter is located at the first position to be greater than the current value supplied to the first light source unit when the filter is located at the second position.

The configuration of Appendix 8 makes it possible to adjust the white balance of the composite light.

(Appendix 9)
The light source device described in Appendix 8, wherein the control unit further performs control to make a current value supplied to the second light source unit when the filter is located at the first position smaller than a current value supplied to the second light source unit when the filter is located at the second position.

The configuration of Appendix 9 makes it possible to adjust the white balance of the composite light while minimizing the decrease in luminance when the filter is in the first position.

(Appendix 10)
The light combining element combines the third light incident from the wavelength conversion element along a first direction and the second light incident from the second light source unit along a second direction intersecting the first direction,
10. The light source device according to claim 1, wherein the filter is provided between the light combining element and the wavelength conversion element.

According to the configuration of Supplementary Note 10, since the second light does not pass through the filter, the filter specifications are simpler than when the second light passes through the filter. This reduces the manufacturing cost of the filter and makes it easier to achieve the desired spectral characteristics.

(Appendix 11)
a first optical element provided on a light incident side of the filter and configured to split the combined light emitted from the light combining element into a first light beam and a second light beam;
a second optical element provided on the light exit side of the filter, the second optical element having a first light entrance area on which the first light flux is incident and a second light entrance area on which the second light flux is incident;
Further equipped with
the filter has a first filter portion on which the first light flux is incident and a second filter portion on which the second light flux is incident,
At the first position of the filter, the first filter portion is disposed at a position facing the first light entrance region of the second optical element, and the second filter portion is disposed at a position facing the second light entrance region of the second optical element,
10. The light source device according to claim 1, wherein, in the second position of the filter, the first filter portion is positioned opposite an area between the first light entrance area and the second light entrance area of the second optical element.

The configuration of Appendix 11 allows the movement distance of the filter between the first position and the second position to be reduced, thereby enabling the light source device to be made smaller.

(Appendix 12)
a cross-sectional shape of the first light incident on the filter is an ellipse having a major axis and a minor axis,
a cross-sectional shape of the third light incident on the filter is circular,
a diameter of the cross-sectional shape of the third light is substantially equal to one of a diameter of the cross-sectional shape of the first light in a direction along the major axis and a diameter of the cross-sectional shape of the first light in a direction along the minor axis,
12. The light source device according to claim 1, wherein the filter is movable in a direction along the axis that is approximately aligned with the major axis or the minor axis.

The configuration of Appendix 12 can reduce color unevenness when switching modes.

(Appendix 13)
A light source device according to any one of claims 1 to 12,
a light modulation device that modulates light including the composite light emitted from the light source device in accordance with image information;
a projection optical device that projects the light modulated by the light modulation device;
A projector equipped with

The configuration of Appendix 13 makes it possible to realize a projector that can switch between a color reproducibility-oriented mode and a brightness-oriented mode.

10...projector, 11...first light source unit, 12...first light source unit, 13...wavelength conversion element, 14, 64...light combining element, 15, 55, 85...filter, 15a...light incidence surface, 16...parallelization element, 17...diffusion device, 21...integrator optical element (first optical element), 22...polarization conversion element (second optical element), 22A...first light incidence area, 22B...second light incidence area, 24...control unit, 27...first light emitting element, 2 9...first phase difference plate (first phase difference element), 85A...first filter section, 85B...second filter section, 100, 120, 130, 140, 150...light source device, 400R, 400G, 400B...light modulation device, 600...projection optical device, LBp, LBs, LBc1, LBc2...blue light (first light), LR, LRp, LRs...red light (second light), LG...green light (third light), L1...first light beam, L2...second light beam.

Claims (13)

a first light source unit that emits a first light of a first wavelength band including a first polarized component and a second polarized component different from the first polarized component;
a second light source unit that emits a second light of a second wavelength band different from the first wavelength band;
a wavelength conversion element that converts the first light into a third light of a third wavelength band different from the first wavelength band and the second wavelength band;
a light combining element that combines the first light, the second light, and the third light and emits a combined light;
a filter into which the third light is incident and which attenuates light of a part of the third wavelength band;
Equipped with
The light combining element is
The first light emitted from the first light source unit is reflected by the first polarization component, and the second polarization component is transmitted, thereby emitting one of the first polarization component and the second polarization component toward the wavelength conversion element;
transmits one of the first light, the second light, and the third light, and reflects the other,
The filter comprises:
A light source device that is movable between a first position where the third light passes through the filter and a second position where the third light does not pass through the filter. The light source device according to claim 1, further comprising a diffusion device that diffuses the first light and the second light. the diffusion device is disposed between the light combining element and the second light source unit,
3. The light source device of claim 2, wherein the diffusion device has a diffusion structure that diffuses the first light and the second light on a first surface onto which the first light reflected by the light combining element is incident, and has a reflective film on a second surface opposite the first surface that reflects the first light and transmits the second light. The light source device according to any one of claims 1 to 3, further comprising a collimating element provided on the light incident side of the filter and configured to substantially collimate the third light. The light source device according to any one of claims 1 to 3, wherein the light incidence surface of the filter intersects with the chief ray of the third light at an angle other than 90 degrees. The first light source unit is
A first light emitting element that emits the first light;
a first phase difference element provided between the first light emitting element and the light combining element and configured to impart a phase difference to the first light;
Equipped with
the first light emitted from the light combining element is incident on the wavelength conversion element,
The light source device according to claim 1 , wherein the first phase difference element is rotatable about an axis that intersects with a light incidence surface of the first phase difference element. The light source device according to any one of claims 1 to 3, further comprising a control unit that controls the current value supplied to the first light source unit when the filter is located at the first position and the current value supplied to the first light source unit when the filter is located at the second position so that they are different from each other. the first light is blue light;
the second light is red light;
the third light is green light;
8. The light source device according to claim 7, wherein the control unit controls the current value supplied to the first light source unit when the filter is located at the first position to be greater than the current value supplied to the first light source unit when the filter is located at the second position. The light source device according to claim 8, wherein the control unit further controls the current value supplied to the second light source unit when the filter is located at the first position to be smaller than the current value supplied to the second light source unit when the filter is located at the second position. The light combining element combines the third light incident from the wavelength conversion element along a first direction and the second light incident from the second light source unit along a second direction intersecting the first direction,
The light source device according to claim 1 , wherein the filter is provided between the light combining element and the wavelength conversion element. a first optical element provided on a light incident side of the filter and configured to split the combined light emitted from the light combining element into a first light beam and a second light beam;
a second optical element provided on the light exit side of the filter, the second optical element having a first light entrance area on which the first light flux is incident and a second light entrance area on which the second light flux is incident;
Further equipped with
the filter has a first filter portion on which the first light flux is incident and a second filter portion on which the second light flux is incident,
At the first position of the filter, the first filter portion is disposed at a position facing the first light entrance region of the second optical element, and the second filter portion is disposed at a position facing the second light entrance region of the second optical element,
4. The light source device according to claim 1, wherein, in the second position of the filter, the first filter portion is positioned opposite an area between the first light entrance area and the second light entrance area of the second optical element. a cross-sectional shape of the first light incident on the filter is an ellipse having a major axis and a minor axis,
a cross-sectional shape of the third light incident on the filter is circular,
a diameter of the cross-sectional shape of the third light is substantially equal to one of a diameter of the cross-sectional shape of the first light in a direction along the major axis and a diameter of the cross-sectional shape of the first light in a direction along the minor axis,
The light source device according to claim 1 , wherein the filter is movable in a direction along the axis that is substantially aligned with the major axis or a direction along the minor axis. A light source device according to any one of claims 1 to 3,
a light modulation device that modulates light including the composite light emitted from the light source device in accordance with image information;
a projection optical device that projects the light modulated by the light modulation device;
A projector equipped with

Images